Conifer Scales are a type of insect which affects most species of pine trees, spruces and firs. Armored or hard scales are only susceptible to topical insecticides during the crawler stage, and at times of heavy infestations, a systemic insecticide may be needed to control the scale. Soft scales have a thinner protective outer later treated throughout the year as needed. Some of the more common Front Range scales include: Pine Needle Scale, Striped Pine Scale, Juniper Scale, Pine Tortoise Scale, Pinyon Needle Scale and although rare, Spruce Bud Scale.
Deciduous shade trees are also affected by scale insects with damage occurring on the bark, branches and twigs as opposed to the foliage. These scales may also be soft or armored and that will dictate which treatment will be the most effective. Oystershell Scale, is an armored scale and is the most prolific and damaging of the scales in the Front Range and will often be found on Aspens, Poplars and Willows though it can attack a variety of species. Kermes Scale feeds on several species of Oak trees though it appears most frequently on Red Oaks in this area. Also an armored shell, these scales are best treated during the crawler stage and with dormant oils during dormancy. European Elm Scale can be a pest of American Elm trees in Denver and is not usually associated with Siberian Elms. Cottony Maple Scale is a soft shelled scale which can be a nuisance for many woody plants though it is easily controlled. This scale will look like small cotton balls on the trunk or twigs and is usually found on Maple trees.